Lithium-ion battery and method for manufacturing the same

Abstract

A lithium ion battery includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive electrode active material. The negative electrode includes a negative electrode active material and a specific metal. A void is located inside the negative electrode active material. The specific metal adheres to an outside surface and an inside surface of the negative electrode active material. The specific metal includes a dissolution potential and a deposition potential. The dissolution potential is lower than a potential at which the positive electrode active material releases Li ions. The deposition potential is higher than a potential at which the negative electrode active material stores the Li ions.

What is claimed is: 
     
         1 . A lithium-ion battery, comprising:
 a positive electrode;   a negative electrode; and   an electrolyte, wherein:
 the positive electrode includes a positive electrode active material; 
 the negative electrode includes a negative electrode active material and a specific metal; 
 a void is located inside the negative electrode active material; 
 the specific metal adheres to an outside surface and an inside surface of the negative electrode active material; 
 the specific metal includes a dissolution potential and a deposition potential; 
 the dissolution potential is lower than a potential at which the positive electrode active material releases lithium ions; and 
 the deposition potential is higher than a potential at which the negative electrode active material stores the lithium ions. 
   
     
     
         2 . The lithium-ion battery according to  claim 1 , wherein the specific metal includes at least one selected from the group consisting of potassium, rubidium, barium, strontium, calcium, sodium, magnesium, aluminum, uranium, titanium, zirconium, manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, copper, mercury, and silver. 
     
     
         3 . The lithium-ion battery according to  claim 1 , wherein the specific metal includes at least one selected from the group consisting of iron, chromium, and nickel. 
     
     
         4 . The lithium-ion battery according to  claim 1 , wherein a ratio of mass of the specific metal to mass of the negative electrode active material is 0.192 to 0.384. 
     
     
         5 . The lithium-ion battery according to  claim 1 , wherein the negative electrode active material is a secondary particle including a plurality of primary particles, and the void is located between the primary particles. 
     
     
         6 . The lithium-ion battery according to  claim 5 , wherein in the negative electrode active material, the specific metal adheres to the inside surface up to a distance of one-fifth or more of a maximum diameter of the secondary particle from a surface of the secondary particle toward a center of the secondary particle on a line segment of the maximum diameter of the secondary particle. 
     
     
         7 . A method for manufacturing a lithium-ion battery, the method comprising:
 preparing a positive electrode including a positive electrode active material;   preparing a negative electrode including a negative electrode active material;   assembling the lithium-ion battery including the positive electrode, the negative electrode, an electrolyte, and a specific metal;   performing first charging of the lithium-ion battery; and   after the first charging, performing second charging of the lithium-ion battery, wherein:
 a void is located inside the negative electrode active material; 
 the specific metal includes a dissolution potential and a deposition potential; 
 the dissolution potential is lower than a potential at which the positive electrode active material releases lithium ions; 
 the deposition potential is higher than a potential at which the negative electrode active material stores the lithium ions; 
 in the assembling the lithium-ion battery, the specific metal is placed so as to be electrically in contact with the positive electrode; 
 the first charging includes performing constant voltage charging of the lithium-ion battery at such a battery voltage that a positive electrode potential becomes higher than the dissolution potential and a negative electrode potential becomes higher than the deposition potential; and 
 in the second charging, the negative electrode potential becomes equal to or lower than the deposition potential.